Abstract The prevalence of sleep disturbances during pregnancy is driven by the normal physiological, physical and hormonal alterations of the pregnancy state. In particular, sleep-disordered breathing (SDB), a common sleep disturbance, characterized by habitual snoring during sleep, has been linked to several adverse pregnancy outcomes, such as pregnancy-induced hypertension (PIH) as well as preterm births. However, these data are generally from cross-sectional studies, with limited control for inherent biases. Of note, near-universal adjustment for the influence of obesity or pregnancy weight gain on SDB often masks its true contribution to PIH. Despite the known complexity of the obesity-SDB relationship, and the increasing public health impact of obesity, the pathway between obesity, SDB and PIH has yet to be investigated with contemporary epidemiologic tools. Therefore, the current study seeks to apply advanced epidemiologic methods to decipher the pathways between SDB, maternal obesity, gestational weight gain and key adverse pregnancy outcomes; PIH and gestational age at birth. In addition, SDB impact on gestational blood pressure trajectory will be examined. In this study, I will pursue the following specific aims: (1) investigate the longitudinal association of SDB and blood pressure, controlling for maternal baseline BMI, gestational weight gain, and other maternal factors; (2) apply mediation analysis to disentangle the complex pathway between obesity, SDB and PIH. I will estimate the total, direct, and indirect effect of obesity on PIH, with SDB as the intervening variable; (3) examine SDB impact on gestational age at birth. The proposed aims will be accomplished using a prospective cohort of 1,673 pregnant women recruited from a large tertiary medical center. Demographic and sleep data, generated by well-validated instruments, were collected from all women, and maternal-perinatal information was abstracted from medical charts. This F32 postdoctoral fellowship will focus on four objectives: 1) didactic education in sleep medicine and research; 2) training in advanced statistical methodology; 3) development of an integrative research track in sleep-epidemiology-perinatology; and 4) growth of professional skills. The proposed training will benefit from a mentoring team with a record of highly productive research in sleep medicine, epidemiology and perinatology. This research will shed light on the role of SDB in adverse maternal-perinatal outcomes. Evidence for the specific impact of SDB, beyond its association with obesity, will provide motivation and rationale to identify `at risk' women among whom early intervention will be most effective. This fellowship will provide comprehensive research, didactic, and professional training necessary to assure development of an independent academic career focused at the critical intersection of sleep medicine, perinatal health, and epidemiology.